ES3014299T3 - Electrical tool - Google Patents

Abstract

The invention relates to a power tool (1), in particular to an angle grinder (2), with a drive motor (4) housed in a housing (3), which drives a rotor shaft (5), with a tool spindle (7) having a tool holder (8) and connected to the rotor shaft (5) by means of an angular gear (6) housed in a gear head (9), with a support plate (10) having a spindle passage (11) in which the tool spindle (7) is rotatably housed, where the support plate (10) has a receiving flange (12) on which a protective cover (13) can be rotatably mounted, the removal of which from the receiving flange (12) is made more difficult at least by a safety device (21). The fixing device (21) is selected from a group comprising at least one fixing pin (20) received in the receiving flange (12), a fixing ring (27) preferably fixed to the receiving flange (12) by means of a snap connection or by means of a press-fit connection, a fixing plate (33) screwed to the support plate (10) by means of a plurality of fixing screws (34), a fixing clip (44) fixed to the support plate (10) and a fixing tab (50) formed on the protective cover (13). (Automatic translation with Google Translate, no legal value)

Description

DESCRIPTION

Power tool

The invention relates to a power tool, in particular an angle grinder, with a drive motor housed in a housing, which drives a rotor shaft, with a tool spindle having a tool housing, which is connected to the rotor shaft by means of an angular gear, which is housed in a gear head, with a bearing plate having a spindle passage, in which the tool spindle is rotatably housed, the bearing plate having a housing flange, on which a protective cover can be rotatably mounted, the removal of which from the housing flange is at least made more difficult by a safety device.

For mounting the protective cover on the bearing plate, a coding is typically provided between the bearing plate mounting flange and the protective cover—and preferably also in the present power tool—which makes it possible to mount the protective cover only in a specific mounting position on the mounting flange and also to remove it again. To this end, axial grooves are provided on the mounting flange, more specifically on its outer cylindrical surface. Radial projections, which are formed on the inner side of a hollow cylindrical mounting flange of the protective cover, engage in these axial grooves in the mounting position. The mounting position generally corresponds to a position that usually does not serve as a working position. After mounting, the protective cover can then be rotated and locked into various working positions by means of a locking pawl.

Such protective covers are intended to protect the power tool user from injury caused by sparks or similar particles generated during use. Furthermore, the protective cover must ensure that, in the event of the insertion tool breaking, the protective cover can withstand fragments of the insertion tool striking the protective cover at very high speeds.

However, if the power tool is used without this protective cover, there is a fairly high risk of injury, so the use of the protective cover is absolutely necessary. Despite these risks, these power tools are frequently used without the corresponding protective cover, contrary to the operating instructions, as the protective cover is perceived as inconvenient by the user. Therefore, various approaches are known from the state of the art to at least make it difficult for the user to remove the protective cover from the power tool.

For example, document DE 10 2019 104 139 A1 shows an angle grinder in which the coding on the protective cover is partially obscured to make it difficult to remove. Furthermore, a stop component, which is screwed onto the bearing plate, is intended to prevent the user from easily removing the protective cover from the angle grinder. To achieve this, the stop component can be screwed onto the bearing plate via a threaded connection, but cannot be removed without first removing the bearing plate.

Document DE 20 2019 100921 U1 describes a power tool comprising a motor with a gear ratio, which is located in a housing. A front tool retaining section is connected to the gear ratio. A cover at least partially covers the front tool retaining section and is provided with a stop element. The cover and the housing have appropriate locking elements for securing the cover to the housing. The stop element has a section that engages in the locking elements of the housing.

Document WO 2020/031866 A1 discloses a power tool with the features of the preambles of claims 1, 5 and 9. This tool may comprise a motor, a force transmission mechanism connected to the motor, a housing for accommodating the motor and the force transmission mechanism, a distal tool retaining section, a cover for covering at least a part of the distal tool retaining section, a first locking mechanism and a second locking mechanism. The first locking mechanism is brought to an unlocked state by activation by the user, while the second locking mechanism is brought to an unlocked state by a separate activation by the user.

Document DE 10 2006 027576 A1 relates to a protective cover clamping device for power tools. It comprises a clamping element for attaching a protective cover to the tool body. The clamping element contains at least one locking element to protect the protective cover from twisting on the power tool body.

Document DE 102006053305 A1 describes a hand-held machine tool for rotating tools, such as disc tools, which is equipped with a machine housing, which has a flange or a machine neck. A protective cover, usually made of sheet metal, is placed on this housing to cover the tool. A torsion guard between the machine neck and the protective cover ensures operational safety. The protective cover is connected to the machine neck by means of a tensioning strap or form-fitting tensioning means and can be released for adjustment.

Document DE 102007052683 A1 relates to a hand-held machine tool, in particular an angle grinder, with a housing and a flanged collar, on which a protective device is mounted, forming a tool area. It is proposed that at least one device be provided for damping and/or compensating for backlash between the housing and the protective device.

Document DE 102009024427 A1 relates to a protective cover for electric hand tools, in particular angle grinders, with a cover plate covering a disc tool, which extends perpendicular to a cover collar. The protective cover can be attached to the machine neck, with at least one form-fitting locking element being provided between the cover collar and the machine neck, which interacts with a corresponding element of the machine neck. A power hand tool device with such a protective cover is also described.

Document DE 101 58 334 C1 relates to an electric handheld tool, in particular an angle grinder, with a protective cover that can be removably attached to the spindle neck. The protective cover has a cylindrical collar, which is arranged around the spindle neck and interacts with a counteracting means on the spindle neck to inhibit rotation. The cam means is connected to a support element outside the collar and is guided radially inward through an interruption in the collar, to interact with the counteracting means. The support element is thereby retained even when separated from the protective cover, preventing it from being lost in the collar.

Document DE 10 2008 000732 A1 describes a hand-held machine tool having a protective cover, which is detachably connected to a support part of the hand-held machine tool. A radially projecting clamping projection is formed on the opening wall delimiting a receiving opening of the protective cover. A support part, to which the protective cover is attached, has a support socket that can be inserted into the receiving opening, in which a clamping notch for the clamping projection is formed.

Document EP 2 119534 A1 describes a protective cover that can be attached to a power tool, in particular an angle grinder, and can be pivoted within a limited angular range relative to the drive spindle into different operating positions. It consists of a body with a wall in the form of a circular sector and several retaining elements arranged coaxially along a pitch arc. These retaining elements engage an opposing element of the power tool to secure the protective cover in the selected position.

However, the solution known from the prior art has proven to be very laborious, so the present invention is based on the objective of reducing the aforementioned disadvantages and providing a power tool, which has a simpler protective cover safety device.

This objective is achieved through the subject matter of the independent claims. Improvements can be derived from the dependent claims.

This object is achieved according to the invention in an electric tool of the type mentioned at the beginning, in that the safety device is selected from a group comprising at least one safety pin housed in the housing flange, a safety ring fastened to the housing flange preferably by means of a locking connection or by means of a press connection, a safety plate screwed to the bearing plate by means of a plurality of safety screws, a safety clip fastened to the bearing plate and a safety tab formed in the protective cover.

This provides simple ways to attach the protective cover to the mounting flange and at least make it difficult for the power tool user to remove it improperly. Furthermore, these safety devices make it easy to identify user tampering. Thus, for example, a safety officer can easily recognize and penalize tampering. Since the power tool itself becomes significantly safer in this way, this can eventually lead to reduced insurance premiums or professional insurance premiums.

In this case, it has proven particularly advantageous that the at least one securing pin can be inserted into a pin receptacle formed in the housing flange after the protective cover has been mounted on the housing flange. Thus, after the protective cover has been mounted on the bearing plate, the at least one securing pin can be inserted into the pin receptacle. In this case, the securing pin can be inserted into the pin receptacle such that the securing pin also protrudes into the axial groove, thereby blocking the corresponding axial groove in the housing flange and thereby preventing disassembly of the protective cover, since the respective radial projection is thereby blocked by the securing pin. In this case, the securing pin is thrust into the pin receptacle. Before removing the protective cover, it must be additionally inserted into the pin housing to release the axial groove again. This allows the radial projection to pass through the safety pin and emerge from the axial groove during removal. The user can therefore remove the protective cover, but only with considerable effort and only in such a way that tampering can be easily detected, for example, during maintenance or an internal company safety check.

Furthermore, it has proven advantageous for the protective cover to have at least one passage for inserting the at least one securing pin into the pin receptacle. This allows the securing pin to be easily inserted from the outside through the passage, which is preferably formed in a mounting flange of the protective cover, into the pin receptacle. However, within the scope of the invention, it is also provided that the securing pin is inserted from the inner circumference of the receptacle flange into the pin receptacle, which opens into the axial groove. In this type of installation, too, the securing pin naturally protrudes through the pin receptacle into the axial groove, thereby blocking the axial groove and thus preventing disassembly of the protective cover.

Removing the safety pin can also be difficult when the pin housing is configured as a blind hole. This makes it impossible for the user to pass the safety pin through the pin housing to remove the protective cover from the bearing plate. For removal, the user would instead have to drill out the safety pin. Therefore, when the protective cover needs to be replaced, the bearing plate must be replaced along with the protective cover.

It has also been particularly successful if the safety device comprises a safety cap, which is secured to the bearing plate by means of the at least one safety pin. In particular, when the safety cap is inserted into the inner side of the housing flange, this allows the at least one safety pin to be removed from the axial groove only if the safety cap has been previously destroyed, which would attract attention during a power tool inspection.

In this context, it has also proven advantageous for the safety cap to have at least ring-shaped projections on the side facing away from the tool receptacle. These projections can, on the one hand, at least partially penetrate the safety pin and, on the other hand, provide a stop for the safety pin, i.e., limit its insertion depth in the pin receptacle and, at the same time, ensure that the protective cover can only be removed from the bearing plate if the safety cap has been previously destroyed mechanically or if the safety pins have been drilled out.

When the safety device is designed as a safety ring, it has proven advantageous to associate the safety ring with a radial collar on which safety lugs are formed. The axial collar first provides a stop surface, which during assembly limits the safety ring to the housing flange. In this regard, the safety lugs can be received in at least part of the axial grooves formed in the housing flange. In this regard, the safety ring is preferably received at least partially on the inside of the housing flange, thereby facilitating its assembly. The safety ring also ensures that the axial grooves are at least partially blocked, so that the protective cover cannot be removed from the housing flange.

Disassembly of the protective cover can also be very simply prevented by a locking ring, which is secured to the housing flange by a locking connection or a press connection. To secure the locking ring to the housing flange, it has proven advantageous to associate locking projections with the safety ring for the formation of a locking connection. In particularly preferred embodiments, these are formed on the safety lugs, which engage in the axial grooves. In this regard, the locking projections engage in locking seats, which in a preferred embodiment are formed on the housing flange in the area of the axial grooves. This makes it possible during assembly to simply place the safety element on the housing flange and lock it there by means of the locking connection.

A very simple attachment of the protective cover to the power tool can also be achieved by means of the safety plate, which is screwed to the bearing plate by means of several safety screws. In this regard, it has proven particularly successful to screw it in from the side facing the tool mount, as this reduces the assembly effort. However, within the scope of the invention, it is also provided that the safety plate is screwed to the bearing plate from the side facing away from the tool mount. This further increases the protection against unauthorized removal of the protective cover, since the bearing plate must now first be removed to remove the protective cover. In addition to safety screws, within the scope of the invention, it is also provided that the safety plate is also attached by forming. In this regard, riveting, punch riveting, deformation joining (clinching, Tox clinching), crimping, and crimping have proven particularly advantageous. Additional options for securing the security plate include bonding, welding, particularly laser welding, vulcanization, or extrusion coating, to make removal of the security plate even more difficult. In this context, it has also proven advantageous for the security screws used for screwing to have a screw lock that prevents unauthorized removal. This can be ensured, for example, by a special screw head shape, which enables the security screw to be screwed into the screw receptacle but prevents loosening; by an insert inserted into the tool receptacle of the screw head; or by a special screw head, which is sheared off by the security screw if a limiting moment is exceeded.

To facilitate mounting the safety device on the power tool, it has also proven successful to have a centering device and/or a centering collar configured on the bearing plate and/or the safety plate. In this context, it has proven particularly advantageous for the centering device to comprise an axial collar, which is configured on the bearing plate. The safety device can then be placed on this axial collar. It has also proven advantageous for the safety plate to be equipped with safety wings that at least partially cover the protective cover. In this regard, the covering can particularly preferably take place in an area into which no axial groove of the coding opens, thereby enabling the user to easily check the alignment of the protective cover relative to the mounting flange. To achieve improved stability of the safety device, it has also proven to be reasonable for the safety wings to be connected to one another by means of a locking ring. This embodiment can also be used, in particular, in the case of a bearing plate whose housing flange is formed free of coding on the outer perimeter. This eliminates the need for coding, which has a positive effect on production efficiency. This means that the protective cover can be easily positioned on the housing flange in any orientation. The axial position of the protective cover on the bearing plate is then fixed by the securing wings or the sealing ring of the closure plate.

When the safety device is designed as a safety clip, it has proven advantageous to associate the safety clip of the safety device with a radially adjustable safety protrusion, which can be inserted into a shape formed on the protective cover. This is preferably formed on the mounting flange of the protective cover. The shape points radially outward. In this way, the safety clip can be easily inserted into the shape when the protective cover is mounted on the receiving flange and the protective cover is in the mounted position. That is, if the axial groove and the radial projections of the coding are flush with each other, then the safety clip and the shape also face each other. By means of the safety clip, whose safety protrusion in this position is inserted into the shape, the protective cover cannot now be removed from the receiving flange. In this regard, the safety protrusion is preferably attached to the safety clip on only one side, preferably on a long side. Alternatively, the safety protrusion can also be held on one or two opposite short sides of the safety clip. In this regard, the safety clip can also be provided in multiple configurations. In this case, the safety clip is held axially in a non-displaceable, but rotatable manner on the receiving flange.

In order to be able to mount the protective cover on the mounting flange, it has also proven particularly advantageous to have an insertion chamfer configured on the safety protrusion. The insertion chamfer allows for simplified mounting of the protective cover on the mounting flange, since this ensures that the safety protrusion can be deflected radially inward when the protective cover is mounted on the mounting flange. In this context, it has also proven successful to have the insertion chamfer designed so that the safety clip of the safety device moves radially perpendicular to the mounting direction during mounting of the protective cover. This ensures that the protective cover can be mounted easily. In this regard, the insertion chamfer is formed on only one side, so that, when the protective cover is removed from the housing flange, the shape restriction, which is formed in the protective cover, prevents radial displacement of the safety clip, whose safety protrusion engages in the shape.

It has also proven advantageous for the safety clamp to be mounted so that it can be moved in a circumferential direction in an annular groove formed in the housing flange of the bearing plate. To hold the safety clamp in the annular groove of the housing flange during assembly, special retaining structures, such as lugs, on the safety clamp, which in a particularly preferred embodiment are triangular in shape, have proven advantageous. After assembly of the protective cover, the safety clamp, whose safety protrusion engages in the shape, is connected to the protective cover in a rotation-resistant manner. This makes it possible to ensure the axial position of the protective cover in the assembly position. At the same time, however, it is also possible to rotate the protective cover and the safety clamp coupled to it in a rotation-resistant manner relative to the bearing plate. When the protective cover is rotated out of the mounting position, the safety protrusion of the safety clip remains radially displaced outwards and inserted into the shape, so that the protective cover can be rotated together with the safety clip.

When the safety device is configured as a safety tab, it has proven advantageous for the safety tab, which is configured on the protective cover, to provide a spring-loaded action. This elastically deforms the safety tab during mounting of the protective cover on the housing flange. When the protective cover is then mounted on the housing flange, the prestressed safety tab moves back into the annular groove configured on the housing flange and thereby secures the protective cover to the housing flange.

However, within the scope of the invention, it has also been shown to be advantageous if the safety tab can be mechanically moved into a safety position. For this purpose, an auxiliary tool, for example, a stamping punch, can be used to press the safety tab into the annular groove after mounting the protective cover on the receiving flange. In this regard, except for an annular groove, the receiving flange can be designed without coding.

The invention is explained in more detail below with several exemplary embodiments shown in the drawings; they show:

Figure 1 a perspective view of the gear head of a power tool with a protective cover in a mounting position,

Figure 2 shows a cross-section through a gear head with a first embodiment of a safety device with a protective cover located in a mounting position,

Figure 3 shows a longitudinal section through the gear head with the first embodiment of the safety device,

Figure 4 is a perspective view of a safety cap, which is part of a second embodiment of the safety device,

Figure 5 shows a fragment through a longitudinal section of a gear head with the safety cap attached to the gear head,

Figure 6 a cross-section through a gear head with the second embodiment of the safety device,

Figure 7 is a perspective view of a safety ring with locking protrusions, which is part of a third embodiment of the safety device,

Figure 8 is a fragment through a longitudinal section of a gear head with the circlip fastened to the gear head of Figure 7,

Figure 9 shows a longitudinal section through the gear head with the third embodiment of the safety device designed as a safety ring with locking protrusions, Figure 10 shows a perspective view of a fourth embodiment of the safety device, Figure 11 shows a fragment through a longitudinal section of a gear head with the fourth embodiment of the safety device attached to the gear head,

Figure 12 is a perspective fragment of a power tool with the fourth embodiment of the safety device,

Figure 13 is a perspective view of a power tool with a fifth embodiment of the safety device designed as a safety plate, which is screwed to the gear head,

Figure 14 shows a perspective view of a bearing plate of the gear head of Figure 13, Figure 15 shows a perspective fragment of a power tool with a further embodiment of the safety device designed as a safety plate,

Figure 16 shows a longitudinal section through a gear head according to Figure 15 with the safety plate serving as a safety device,

Figure 17 is a perspective view of a bearing plate of the gear head of Figure 16, Figure 18 is a further embodiment of a safety device designed as a safety plate with safety wings,

Figure 19 shows a further embodiment of the security plate with a locking ring,

Figure 20 shows a longitudinal section through a gear head with a securing plate, which is screwed from the side facing away from the tool housing to the bearing plate,

Figure 21 shows a detailed perspective view of a bearing plate, in which a safety clamp is housed, which serves as a safety device,

Figure 22 is a perspective view of the safety clip in Figure 21,

Figure 23 a sectional view along a longitudinal section through the gear head of Figure 21,

Figure 24 a detailed cutaway view of the protective cover attached to the housing flange by means of the safety clip,

Figure 25 a cross-section through a gear head with a protective cover held by the safety clip,

Figure 26 is a perspective view of a protective cover, in which the safety device is designed in the form of a safety tab,

Figure 27 is a perspective view of the protective cover which can be fastened to the bearing plate housing flange by means of the safety tab,

Figure 28 is a perspective view of a protective cover, in which the safety device is configured in a further embodiment of a safety tab,

Figure 29 is a perspective view of the protective cover of Figure 28, which can be fastened to the receiving flange of the bearing plate by means of the additional embodiment of the safety tab,

Figure 30 shows a perspective view of a protective cover, in which a third embodiment of a safety tab is configured, and

Figure 31 is a perspective view of the protective cover secured by the third embodiment of the safety tab to the bearing plate housing flange.

Figure 1 shows a perspective view of a fragment of a power tool 1, specifically an angle grinder 2. This has a housing 3 in which a drive motor 4 is housed. This drive motor 4 rotatably drives a rotor shaft 5, which is connected to a tool spindle 7 via an angle gear 6 and also rotatably drives the latter. A tool holder 8 is formed at the end of the tool spindle 7, to which an insert tool, which is designed, for example, as a grinding or separating disc, can be clamped. The angular gear 6 is mounted in a gear head 9, which is connected to a bearing plate 10, which is bolted to the gear head 9. A spindle passage 11 for the tool spindle 7 is configured on the bearing plate 10, in which the tool spindle 7 is rotatably mounted. A mounting flange 12 is configured on the bearing plate 10, on which a protective cover 13 can be rotatably mounted to protect the user during machining of workpieces. For mounting the protective cover 13, a coding 14 is formed between the protective cover 13 and the receiving flange 12, which enables the user to insert the protective cover 13 only in one mounting position on the receiving flange 12. This coding 14 consists in the shown embodiment of a plurality of axial grooves 15 formed on the outer surface of the receiving flange 12, in which radial projections pointing inwards 16, which are formed on a mounting flange 17 of the protective cover 13, engage. In the mounted state, i.e. when the protective cover 13 is inserted onto the receiving flange 12, the radial projections pointing inwards 16 of the protective cover 13 engage in an annular groove 18, which is formed on the receiving flange 12. Guided within this annular groove 18, the user is enabled to rotate the protective cover 13, to adapt the protective cover 13 to different working positions. However, an axial displacement of the protective cover 13 in this respect by means of the coding 14 is only possible in the assembly position.

In the embodiment shown in Figure 1, several passages 19 can be seen in the protective cover 13, through which, after mounting the protective cover 13 on the receiving flange 12, safety pins 20 can be inserted, which form a safety device 21, and with which the removal of the protective cover 13 from the receiving flange 12 is at least made more difficult. The function of these safety pins 20 is explained in even more detail below with the help of Figures 2 and 3.

Figure 2 shows a cross-section of the cut bearing plate 10 of the gear head 9. From this it is clear that in the assembled position, shown in Figure 2, the passages 19 are flush with pin receptacles 22, which are formed in the mounting flange 17. In this alignment shown in Figure 2, the securing pins 20 can now be inserted through the passages 19 of the protective cover 13 into the pin receptacles 22, which are formed in the bearing plate 10. In this case, in the assembled state, the securing pins 20 protrude beyond the pin receptacles 22 and protrude into the axial groove 15 and block the radial projections 16 in such a way that the protective cover 13 cannot be removed from the housing flange 12 in the assembled position either. That is, the securing pins 20 are blocked by the securing pins 20. a part of the axial grooves 15 of the coding 14, so that disassembly of the protective cover 13 is not possible. A torsion of the protective cover 13 guided in the annular groove 18 from the assembly position to the working position is also possible in an unchanged manner.

In this respect, the locking of the protective cover 13 attached to the receiving flange 12 of the bearing plate 10 by means of the securing pins 20 is also clear once again from the longitudinal section, which is represented in figure 3. In the embodiment example represented in figures 1 to 3, 3 securing pins 20 are used. However, it is also possible to use any other number of securing pins 20.

In a second embodiment of the safety device 21, shown in FIGS. 4 to 6, the safety device 21 comprises, in addition to the safety pin 20, a safety cap 23. A perspective view of the safety cap 23, which is preferably made of plastic, is shown in FIG. 4. From this, projections 24 in particular become visible, which on the one hand serve to mount the safety cap 23 on the receiving flange 12 and on the other hand provide a stop 26 for the safety pin 20, as can be seen in particular from the detailed view shown in FIG.

From this figure 5 it is clear in particular that the safety pin 20 in this embodiment passes radially through an opening 25 formed in the safety cap 23 and then comes into contact with the projection 24. In this respect, the projection 24 limits the insertion depth of the safety pin 20, so that its assembly is facilitated.

As can also be seen from the cross section shown in Figure 6, the safety pin 20 is in this embodiment also received in the pin receptacle 22, which is formed in the bearing plate 10. However, the safety pin 20 in this respect protrudes into the safety cap 23, which is arranged on the inner circumferential side of the receiving flange 12 of the bearing plate 10. In this case, the safety pin 20 comes into contact with one of the projections 24, which in the embodiment shown are formed on the side directed away from the tool receptacle 8. The safety cap 23 is secured to the bearing plate 10 by means of the safety pin 20. In the embodiment shown here, only one safety pin 20 is used, but within the scope of the invention, it is also provided that the safety pin 20 is provided multiple times. In this respect, the safety cap 23 ensures that the safety pin 20 is prevented from being drilled out of the annular groove 18 by the user through the pin receptacle 22, since the safety cap 23 - specifically the projection 24 - represents a stop 26, which effectively prevents manipulation by the user and thus prevents the user from removing the protective cover 13. In this respect, the safety cap 23 is received in the intermediate space, which is delimited by the receiving flange 12 and the spindle passage 11.

Figure 7 shows a third embodiment of the safety device 21, which comprises a safety ring 27, which is secured to the receiving flange 12 by means of a locking connection. For this purpose, locking projections 28 are formed on the safety ring 27, specifically on safety lugs 29, which are associated with a radial collar 30.

As can be seen in particular from Figure 8, which shows a detail of the safety device 21 fastened to the bearing plate 10 according to the third embodiment, the safety projections 29 engage in the axial grooves 15 formed in the housing flange 12. In this case, the locking projections 28 are inserted into locking seats 31 formed in the housing flange 12 of the bearing plate 10. The path for the radial projections 16 is blocked by the safety projections 29. Due to the locking connection between the safety ring 27 and the housing flange 12, it is not possible to remove the protective cover 13 without destroying the safety ring 27.

In this respect, the longitudinal section through the power tool 1 shown in Figure 9 once again clearly shows that the safety projections 29 of the safety ring 27 prevent the protective cover 13 from being removed. Figure 9 furthermore shows that the radial collar 30 comes into contact with the end face of the housing flange 12, while a hollow cylindrical section 32 of the safety ring 27 rests on the inner circumferential side of the housing flange 12.

A further embodiment of the securing device 21, which comprises a securing ring 27, is shown in Figure 10. In this embodiment, the securing ring 27 is attached to the housing flange 12 by means of a press connection. Similar to the securing ring 27 according to Figures 7 to 9, the securing ring 27 shown in Figure 10 also has a radial collar 30, on which securing lugs 29 are formed. These securing lugs 29 engage on one side in the axial grooves 15 and also form the press connection, with which the securing ring 27 is attached to the housing flange 12.

The detailed view shown in Figure 11 again shows the locking ring 27 fastened to the housing flange 12 of the bearing plate 10 by means of a press connection. In this case, it can be clearly seen that the locking lugs 29 engage in the axial grooves 15 and thus prevent the protective cover 13 from the mounting flange 17 of the bearing plate 10 from being separated by the radial projections 16. However, it is also clear from Figure 11 that the radial collar 30 of the locking ring 27 abuts the end face of the housing flange 12, while a hollow cylindrical section 32 of the locking ring 27 rests on the inner circumferential side of the housing flange 12, similar to what was already the case in the embodiment according to Figures 7 to 9.

Figure 12 shows a perspective view of the locking ring 27 secured to the housing flange 12 by means of a press connection. It is clearly visible that its locking lugs 29 engage in the axial grooves 15 formed in the housing flange 12 of the bearing plate 10. The protective cover 13, which has been omitted from the figure 12 for the sake of clarity, can be rotated—guided in the annular groove 18 of the housing flange 12. However, disassembly is impossible because the axial grooves 15 are blocked by the locking lugs 29.

Figure 13 shows a further embodiment of the safety device 21, in which the safety device 21 is designed as a safety plate 33, which is screwed to the bearing plate 10 by means of a plurality of safety screws 34. The screwing in takes place from the side facing the tool receptacle 8. The safety screws 34 are each associated with a screw lock 35 to prevent unauthorized loosening of the safety screws 34. In the exemplary embodiment shown, this screw lock 35 has a specially shaped screw head 36, which makes it possible to screw the safety screws 34 into the screw receptacles 37 formed in the bearing plate 10, but loosening of the safety screws 34 is not possible. In the embodiment shown in Figure 13, the safety plate 33 has radial safety wings 38 formed thereon, which partially cover the screw heads 37. axial grooves 15. These also facilitate assembly, since this promotes alignment or centering of the safety plate 33. In this case, the safety plate 33 can be made in one piece, as shown in Figure 13, or in several pieces, such as a sheet metal stamped bending part, a casting made of light metal and/or plastic, in this case in particular reinforced with glass fibers.

Figure 14 also shows a perspective view of a bearing plate 10 of the gear head 9. In this embodiment, a centering 39 is formed on the end face of the receiving flange 12, which enables alignment of the safety plate 33 relative to the bearing plate 10.

In the embodiment of the securing plate 33 shown in FIG. 15, the securing plate 33 covers the openings of the axial grooves 15 formed in the bearing plate 10, so that a coding 14 between the housing flange 12 and the protective cover 13 can be dispensed with. In particular, the housing flange 12 can thereby be designed free of coding. That is, the protective cover 13 can now be inserted onto the housing flange 12 at any position and is then axially secured by the securing plate 33, which is screwed unchanged into the bearing plate 10 by means of the securing screws 34.

Figure 16 shows a longitudinal section of the protective cover 13 attached to the bearing plate 10 by means of the safety plate 33. From this it also becomes clear once again that the safety plate 33 covers the radial projections 16 of the protective cover 13, which in the embodiments described above were part of the coding 14.

From Figure 16, the configuration of the bearing plate 10 can also be seen. It is clear here that the receiving flange 12 ends in a shoulder 40, with which the protective cover 13 comes into contact. Furthermore, in the area of the shoulder 40, a recess 41 can be seen, which serves to receive a sealing ring 42. Furthermore, on the receiving flange 12, a centering collar 51 can be seen, which serves as a centering 39 and which promotes centering of the safety plate 33.

Figure 17 again shows the configuration of the associated bearing plate 10 in an isolated perspective view. Particularly recognizable here is the shoulder 40, against which the protective cover 13 comes into contact in the assembled state. Furthermore, Figure 17 also shows the screw receptacles 37, into which the securing plate 33 is screwed firmly, and the centering collar 51, on which the securing plate 33 is centered or aligned.

Figure 18 shows a further embodiment of the safety plate 33. In this case, the diameter of the safety plate 33 is dimensioned such that the axial grooves 15, which are formed in the receiving flange 12, are not covered. For holding the protective cover 13, safety wings 38 are formed on the safety plate 33, which locally encompass the protective cover 13, in order to hold its axial positions to the receiving flange 12.

A further embodiment of the safety plate 33 is shown in Figure 19. In this embodiment, which is a further development of the embodiment in Figure 18, the safety wings 38 are connected to one another by means of a locking ring 43, whereby the contact surface of the safety plate 33 with the protective cover 13 can be increased. In this embodiment too, the safety plate 33 is dimensioned such that the axial grooves 15 are not covered.

In the embodiment shown in Figure 20, the screwing of the safety plate 33 into the bearing plate 10 takes place from the side facing away from the tool receptacle 8. Thus, to remove the protective cover 13, the bearing plate 10 must first be removed, which offers increased protection against unauthorized removal of the bearing plate 10.

A further embodiment according to the invention is shown in Figures 21 to 25. In this embodiment, the safety device 21 comprises at least one safety clip 44 with a radially displaceable safety protrusion 45. As can be seen from Figure 21, the safety clip 44 is received in the annular groove 18 of the bearing plate 10 and held therein by means of nodes 46, whereby the assembly of the protective cover is facilitated.

These nodes 46 can be recognized in particular in the perspective view of the safety clip 44 shown in Figure 22. It can also be seen from Figure 22 that the safety protuberance 45 is attached to the safety clip 44 only on one short side. An insertion chamfer 47 is formed on the safety protuberance 45 of the safety clip 44.

This insertion chamfer 47 ensures that when the protective cover 13 is pushed onto the receiving flange 12, the safety protrusion 45 can move back radially - i.e. perpendicular to the mounting direction 48 of the protective cover 13 -, as shown in Figure 23. Only when the radial projections 16 of the protective cover 13 are received in the annular groove 18, the safety protrusion 45 again moves radially outward into a shape 49, which is formed on the mounting flange 17 of the protective cover 13, as can be seen from Figure 24. Since the insertion chamfer 47 is only formed on the side of the safety protrusion 45 facing the tool receptacle 8, it is ensured that when an attempt is made to remove the protective cover 13 from the receiving flange 12, the safety protrusion 45 cannot come out. of the 49th conformation.

The sectional view shown in Figure 25 shows the protective covers 13 attached to the receiving flange 12 in an operating position. As shown in Figure 25, the safety protrusion 45 is also inserted in the operating position into the shape 49, which is formed on the mounting flange 17 of the protective cover 13. In this way, the protective cover 13 is connected in a rotation-resistant manner to the safety clip 44, so that the safety clip 44 can circulate in a guided manner in the annular groove 18.

26 shows a protective cover 13 having a securing tab 50, which is plastically deformed by a stamping tool after the protective cover 13 has been mounted on the housing flange 12 (not shown in FIGS. 26 and 27). The deformed securing tab 50 engages in the annular groove 18 formed on the housing flange 12 of the bearing plate 10, as can be seen from FIG. 27. This prevents the protective cover 13 from being removed from the housing flange 12.

A similar design is visualized in the protective covers shown in Figures 28 and 29. In this respect, the safety flange 50 can be easily plastically deformed, for example bent, since the safety flange 50 is connected at only one end to the mounting flange 17 of the protective cover 13. That is, if the protective cover 13 is now received on the receiving flange 12 - as shown in Figure 29 - the safety flange 50 can be mechanically displaced in the annular groove 18, which is formed in the bearing plate 10.

Figure 30 and Figure 31 show a further embodiment of the safety device 21, in which the safety tab 50, which is formed on the protective cover 13, provides a spring action. When the protective cover 13 is slid over the housing flange 12, the safety tab 50 elastically moves radially outward. If the protective cover 13 is now slid over the housing flange 12, the safety tab 50 springs into the annular groove 18, which is formed on the housing flange 12. In this way, the protective cover 13 is secured to the housing flange 12.

Depending on the material used and/or the material thickness, the desired spring action of the safety flap 50 shown in Figures 30 and 31 may not be achieved. In this case, the protective cover 13 is first slid onto the receiving flange 12 with the undeformed safety flap 50. After assembly, the safety flap 50 is then plastically deformed with the aid of a stamping punch and engages in the annular groove 18, so that the protective cover 13 can no longer be removed from the receiving flange 12 of the bearing plate 10 by the user.

List of reference numbers

1 power tool

2 angle grinders

3 casing

4 drive motor

5 rotor shaft

6 angular gear

7 tool spindle

8 tool housing

9 gear head

10 bearing plate

11 screw pitch

12 housing flange

13 protective cover

14 coding

15 axial slot

16 radial projection

17 mounting flange

18 annular groove

19 step

20 safety pin

21 safety device

22 pin housing

23 safety hood

24 outgoing

25 opening

26 stop

27 safety ring

28 interlocking protrusion

29 security appendix

30 radial collar

31 interlocking seat

32 hollow cylindrical section

33 security plate

safety thyme

thyme insurance

screw head

screw housing

safety wings

centered

flange

penetration

annular seal

locking ring

safety clamp

safety bump

knot

introductory chamfer

assembly direction

conformation

security tab

centering collar

Claims (9)

1. Power tool (1), in particular an angle grinder (2), with a drive motor (4) housed in a housing (3) and driving a rotor shaft (5), with a tool spindle (7) having a tool housing (8) connected to the rotor shaft (5) via an angle gear (6) and mounted in a gear head (9), with a bearing plate (10) having a spindle passage (11) in which the tool spindle (7) is rotatably mounted, the bearing plate (10) having a housing flange (12) on which a protective cover (13) can be rotatably mounted, the removal of which from the housing flange (12) is at least made more difficult by a safety device (21), the safety device (21) having at least one safety pin (20) housed in the housing flange (12), characterized in that the at least one safety pin (20) after mounting the protective cover (13) on the receiving flange (12) is inserted into a pin receptacle (22) formed on the receiving flange (12) and protrudes into an axial groove (15) of the receiving flange (12), whereby a corresponding axial projection (15) of the protective cover (13) is blocked on the receiving flange (12) and thereby prevents disassembly of the protective cover (13). 2. Power tool (1) according to claim 1, characterized in that at least one passage (19) for inserting the at least one safety pin (20) into the pin receptacle (22) is configured on the protective cover (13). 3. Power tool (1) according to one of claims 1 or 2, characterized in that the safety device (21) comprises a safety cap (23), which is fastened to the bearing plate (10) by means of the at least one safety pin (20), and in particular characterized in that the safety cap (23) is inserted into the inner side of the housing flange (12). 4. Power tool (1) according to claim 3, characterized in that the safety cap (23) has at least ring-shaped projections (24) on the side facing away from the tool housing (8). 5. Power tool (1), in particular an angle grinder (2), with a drive motor (4) housed in a housing (3) which drives a rotor shaft (5), with a tool spindle (7) having a tool housing (8) which is connected to the rotor shaft (5) by means of an angle gear (6) which is housed in a gear head (9), with a bearing plate (10) having a spindle passage (11), in which the tool spindle (7) is rotatably housed, the bearing plate (10) having a housing flange (12), on which a protective cover (13) can be rotatably mounted, the removal of which from the housing flange (12) is at least made more difficult by a safety device (21), the safety device (21) having a safety plate (33) screwed to the bearing plate (10) by means of a plurality of safety screws (34), which plate is arranged centrally with respect to the tool spindle (7), characterized in that the screwing of the safety plate (33) into the bearing plate (10) takes place from the side facing the tool receptacle (8) and the safety screws (34) used for screwing have a screw lock against unauthorized removal. 6. Power tool (1) according to claim 5, characterized in that a centering (39) and/or a centering collar (51) is formed on the bearing plate (10) and/or on the safety plate (33). 7. Power tool (1) according to claim 6, characterized in that the centering (39) comprises an axial collar, which is configured on the bearing plate (10). 8. Power tool (1) according to one of claims 5 to 7, characterized in that safety wings (38) are associated with the safety plate (33), which at least partially cover the protective cover (13), and in particular characterized in that the safety wings (38) are connected to one another by means of a locking ring (43). 9. Power tool (1), in particular angle grinder (2), with a drive motor (4) housed in a housing (3) which drives a rotor shaft (5), with a tool spindle (7) having a tool housing (8), which is connected to the rotor shaft (5) by means of an angle gear (6), which is housed in a gear head (9), with a bearing plate (10) having a spindle passage (11), in which the tool spindle (7) is rotatably housed, the bearing plate (10) having a housing flange (12), on which a protective cover (13) can be rotatably mounted, the removal of which from the housing flange (12) is at least made more difficult by a safety device (21), characterized in that the safety device (21) is selected from a group comprising a safety ring (27) fastened to the housing flange (12) preferably by means of a locking connection or by means of a locking connection. pressing, a safety clip (44) fastened to the bearing plate (10) with a radially adjustable safety protuberance (45) and a plastically deformable safety flange (50), formed in the protective cover (13), providing the interlocking connection (27) interlocking protuberances (28), which are formed in safety appendages (29) of a radial collar (30) of the safety ring (27), and axial grooves (15) being formed on the cylindrical surface of the outer side of the housing flange (12), and the locking protuberances (28) being configured on the safety appendages (29), which engage in the axial grooves (15).